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# ==========================================================================

# -*- coding: utf-8 -*-
# BSD 3-Clause License
#
# Copyright (c) 2017
# All rights reserved.
# Copyright 2022 Huawei Technologies Co., Ltd
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# * Redistributions of source code must retain the above copyright notice, this
#   list of conditions and the following disclaimer.
#
# * Redistributions in binary form must reproduce the above copyright notice,
#   this list of conditions and the following disclaimer in the documentation
#   and/or other materials provided with the distribution.
#
# * Neither the name of the copyright holder nor the names of its
#   contributors may be used to endorse or promote products derived from
#   this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# ==========================================================================

# Copyright (c) OpenMMLab. All rights reserved.
import argparse
import os.path as osp
import time

import mmcv
import numpy as np
import torch
from mmcv import Config
from mmcv.parallel import MMDataParallel
from mmcv.runner import load_checkpoint, wrap_fp16_model

from mmseg.datasets import build_dataloader, build_dataset
from mmseg.models import build_segmentor


def parse_args():
    parser = argparse.ArgumentParser(description='MMSeg benchmark a model')
    parser.add_argument('config', help='test config file path')
    parser.add_argument('checkpoint', help='checkpoint file')
    parser.add_argument(
        '--log-interval', type=int, default=50, help='interval of logging')
    parser.add_argument(
        '--work-dir',
        help=('if specified, the results will be dumped '
              'into the directory as json'))
    parser.add_argument('--repeat-times', type=int, default=1)
    args = parser.parse_args()
    return args


def main():
    args = parse_args()

    cfg = Config.fromfile(args.config)
    timestamp = time.strftime('%Y%m%d_%H%M%S', time.localtime())
    if args.work_dir is not None:
        mmcv.mkdir_or_exist(osp.abspath(args.work_dir))
        json_file = osp.join(args.work_dir, f'fps_{timestamp}.json')
    else:
        # use config filename as default work_dir if cfg.work_dir is None
        work_dir = osp.join('./work_dirs',
                            osp.splitext(osp.basename(args.config))[0])
        mmcv.mkdir_or_exist(osp.abspath(work_dir))
        json_file = osp.join(work_dir, f'fps_{timestamp}.json')

    repeat_times = args.repeat_times
    # set cudnn_benchmark
    torch.backends.cudnn.benchmark = False
    cfg.model.pretrained = None
    cfg.data.test.test_mode = True

    benchmark_dict = dict(config=args.config, unit='img / s')
    overall_fps_list = []
    for time_index in range(repeat_times):
        print(f'Run {time_index + 1}:')
        # build the dataloader
        # TODO: support multiple images per gpu (only minor changes are needed)
        dataset = build_dataset(cfg.data.test)
        data_loader = build_dataloader(
            dataset,
            samples_per_gpu=1,
            workers_per_gpu=cfg.data.workers_per_gpu,
            dist=False,
            shuffle=False)

        # build the model and load checkpoint
        cfg.model.train_cfg = None
        model = build_segmentor(cfg.model, test_cfg=cfg.get('test_cfg'))
        fp16_cfg = cfg.get('fp16', None)
        if fp16_cfg is not None:
            wrap_fp16_model(model)
        if 'checkpoint' in args and osp.exists(args.checkpoint):
            load_checkpoint(model, args.checkpoint, map_location='cpu')

        model = MMDataParallel(model, device_ids=[0])

        model.eval()

        # the first several iterations may be very slow so skip them
        num_warmup = 5
        pure_inf_time = 0
        total_iters = 200

        # benchmark with 200 image and take the average
        for i, data in enumerate(data_loader):

            torch.cuda.synchronize()
            start_time = time.perf_counter()

            with torch.no_grad():
                model(return_loss=False, rescale=True, **data)

            torch.cuda.synchronize()
            elapsed = time.perf_counter() - start_time

            if i >= num_warmup:
                pure_inf_time += elapsed
                if (i + 1) % args.log_interval == 0:
                    fps = (i + 1 - num_warmup) / pure_inf_time
                    print(f'Done image [{i + 1:<3}/ {total_iters}], '
                          f'fps: {fps:.2f} img / s')

            if (i + 1) == total_iters:
                fps = (i + 1 - num_warmup) / pure_inf_time
                print(f'Overall fps: {fps:.2f} img / s\n')
                benchmark_dict[f'overall_fps_{time_index + 1}'] = round(fps, 2)
                overall_fps_list.append(fps)
                break
    benchmark_dict['average_fps'] = round(np.mean(overall_fps_list), 2)
    benchmark_dict['fps_variance'] = round(np.var(overall_fps_list), 4)
    print(f'Average fps of {repeat_times} evaluations: '
          f'{benchmark_dict["average_fps"]}')
    print(f'The variance of {repeat_times} evaluations: '
          f'{benchmark_dict["fps_variance"]}')
    mmcv.dump(benchmark_dict, json_file, indent=4)


if __name__ == '__main__':
    main()
